[Oxidative stress biomarkers determination in urine samples in the group of medical students exposed to tobacco smoke].

Cigarette smoking constitutes one of the main sources of exposure to cancerogenic and procancerogenic xenobiotics in the human population. Smoking is not only a bad habit among adults but also among young people. Despite many anti-tobacco campaigns undertaken by European Union countries still the smoking percentage among young people is high and does not decrease in the recent years. Cigarettes smoking induces formation of reactive oxygen species and increases lipids peroxidation, which ultimately results in the production of MDA (malondialdehyde)--one of the oxidative stress biomarkers. Exposure to oxidative stress and the consequences of its influence can be measured by redox parameters monitoring. One of these methods is determination of total antioxidant activity by means of FRAP test (Ferric Reducing Antioxidant Power) in biological samples. The aim of this work was the evaluation of free radical processes increase related to tobacco smoke exposure by measurement of total antioxidant activity FRAP and MDA concentration in urine samples of medical students. In our study the authors'--designed questionnaire regarding the assessment of exposure to tobacco smoke and chosen xenobiotics was used. The investigated group included 134 students of 1-st and 2-nd year of study at Faculty of Medicine and Dentistry Division in Zabrze, Silesian Medical University. 85 students provided urine samples for further analysis. In the study group 40 students were active smokers and the control group consisted of 45 nonsmokers. The mean MDA concentrations in smoking students group were higher in comparison to the control group of non-smoking students. In the group of students exposed to second-hand smoke MDA concentrations were significantly higher in comparison to the group of students non-exposed to second hand smoke. The values of FRAP parameter were significantly higher for students who smoked in comparison with students non-exposed to tobacco smoke. Students exposed to second hand smoke had slightly higher FRAP values in comparison to smoking students. Exposure to tobacco smoke increased the intensity of free radical processes. Our study confirmed the harmful influence of second hand smoke that resulted in observed higher concentrations of determined biomarkers in the group of passive smoking students.